The d-electron configurations of `Cr^(2+), Mn^(2+), Fe^(2+) and Co^(2+)` are `d^(4), d^(5), d^(6) and d^(7)` respectively. Which one of the following will exhibit minimum paramagnetic behaviour -

Options

A. `[Mn(H_(2)O_(6)]^(2+)`
B. `[Fe(H_(2)O)_(6)]^(2+)`
C. `[Co(H_(2)O)_(6)]^(2+)`
D. `[Cr(H_(2)O)_(6)]^(2+)`

Answer

C

Explanation

The given complexes are all outer orbital complex
`Mn^(2+)rarrd^(5)" system"rarr` 5 unpaired electrons
`Fe^(2+) rarr d^(5)" system "rarr 4` unpaired electrons
`Co^(2+) rarr d^(7)" system "rarr 3` unpaired electrons
`Cr^(2+)rarrd^(4)" system "rarr 4` unpaired electrons